import java.util.*;
public class Example04 {
    public static void main(String[] args) {
        long startTime = System.currentTimeMillis();
        Scanner sc = new Scanner(System.in);
        int i = sc.nextInt();
        List<Integer> a=new ArrayList<>();
        for (int j = 0; j < i  ; j++) {
            a.add(sc.nextInt());
        }
        long start = System.currentTimeMillis();
//        System.out.println(a);
        for (int j = 0; j < a.size()  ; j++) {
            for (int k = 0; k < a.size() ; k++) {
                if (a.get(k)==a.get(j)&&k!=j) {
                    a.remove(k);
//                    System.out.println("---");
                }
            }
        }
        System.out.println(a.size());
        long endTime = System.currentTimeMillis();
        System.out.println("程序运行了"+(endTime-startTime)/1000+"秒");

    }
}
